Fascia Biosystems - Scar Recollagenation

Scar Recollagenation

Steven A. Burres, MD. Laryngoscope 108: September 1998

Objectives: This study was designed to show that native collagen could be regenerated in an area of prior tissue loss. Study Design: Prospective. Methods: Preserved, irradiated human cadaver fascia lata was inserted intradermally to restore topographic skin irregularities. Graft insertion was performed through a skin perforation created by a sterile, hypodermic 20-gauge needle hole into an intradermal pocket. Eighteen subjects with posttraumatic depressions were treated over a 13-month period and examined periodically afterward. Biopsies of selected sites were taken. Results: Of the 44 defects treated in the study group, 14 were judged to be excellent or resolved, 23 were improved, and seven were unchanged at 24 weeks' followup. Biopsies showed graft preservation and fibroblast invasion at 12 weeks. Discussion: Recollagenation is the application of a stimulator material into an area of prior collagen destruction to induce collagen production. Commonly, banked human cadaver fascia has been used to enhance the tissue volume in depressed acne scars, but this process has been successfully performed on a variety of postinflammatory and posttraumatic lesions. The process of fascia graft assimilation into human skin is demonstrated histologically. Conclusion: Recollagenation is an effective process for elevation of depressed, posttraumatic scars. Key Words: collagen, graft, scar, fascia, skin.

Laryngoscope, 108:1394-1397, 1998

Introduction

Contour irregularities in scars are commonplace and many techniques have been reported to restore tissue volume in regions of depletion.[1-5] Bovine collagen may temporarily level imbalances, and long-term success in tissue enhancement has been reported with a variety of graft materials, including banked dura, fascia lata, host scar, and prepared dermis.[1-6] Exogenous materials such as silicone may induce an inflammatory response that results in collagen deposition.[1,2] Even the trauma of simply incising fibrous attachments may blunt rhytids and depressions to improve skin topography, presumably by additional scar formation.[6]

When defect restoration cannot be accomplished with full-thickness skin containing normal appendages, topographic restoration with thickened, native collagen may be the optimal alternative. Recollagenation has been defined as the process of inducing an endogenous collagen reaction in an area of prior collagen loss, tpically in response to a stimulator material. This report demonstrates that banked, irradiated cadaver fascia lata can effectively promote tissue filling in the dermis.

Subjects and Technique

Eighteen patients (11 men, seven women; age range, 19-57y) with healed, depressed, posttraumatic facial scars were treated by recollagenation between January 1995 and February 1996. Injuries were from minor trauma (lacerations and blunt trauma), varied in size from 3 mm to 15 mm, and were all more than 1 year old. Scars were in the following locations: forehead (n = 13), cheeks (n = 18), mouth and chin (n = 7), and nose (n = 6). Treatment was contraindicated in inflamed areas, e.g., active acne sites, and limited to defects in the face and neck regions. Prior or active therapy with isotretinoin was permissible.

After documentation by detailed, close-up photography, each spot was marked with gentian violet.[3,4] The skin was cleansed with povidone-iodine and alcohol. Anesthesia was performed by the injection of 1% lidocaine mixed in a 1:100,000 solution of epinephrine and buffered with sodium bicarbonate. A sterile, hypodermic 22-gauge needle was introduced at the periphery of the defect and the restricting vertical subcutaneous scar bands were divided to create a trans-scar pocket. Chips of banked fascia lata were then inserted into the pocket through the entry perforation. The skin was cleansed with hydrogen peroxide and the treatment site was coated with collodion (Mallinckrodt, Paris, KY).

A regimen of 3 days of antibiotic therapy was prescribed and the use of a moisturizing cream and sunblock were recommended. Tissue biopsies were taken from select volunteers prior to treatment and periodically thereafter, in which instances all graft sites were replaced with matching, posterior-cervical punch grafts.

Results

Although the time course and intensity of the subsequent tissue reaction varied depending on skin thickness and the type of defect of lesion being treated, grafted sites were tpically ecchymotic for 3 to 4 days and remained erythematous and edematous for 2 to 6 weeks.[3,4] When it occurred, mild surface erythema lasted 1 to 5 months. Persistent discoloration occured occasionally in dark-haired, dark-eyed individuals in the midface, but was rarely clinically significant. In smaller lesions, defects were no longer detectable, or only a fine hypervascularity remained. The forehead, nose, and neck responded particularly well to treatment, although consistent improvement could be obtained in any treated site.


Fig. 1. Untreated, depressed ulcer demonstrates the loss of dermal appendages, dermal thinning, and collagen bands binding the base of depression to deeper tissues that are common after acne.	Fig. 2. Six weeks after implantation, the graft fills a wide, middermal zone. A dense lymphocyte infiltration was invoked.

Allergic reactions, infection, or overt scar hypertrophy did not occur. Incomplete restoration could be anticipated in lesions deeper than the graft thickness, which was approximately 1 to 2 mm, unless an exuberant collagen reaction was provoked. Furthermore, pocket widening by graft pressure should occur in the internal as well as external direction, halving the external effect. If the graft tracked subcutaneously or spread into urrounding areas from inaccurate pocket formation, the effect was minimized. Graft extrusion through the original needle track occurred in two instances.

Fig. 3. (A) A section at 12 weeks shows the persistence of the graft, which can be clearly identified by several features. Its collagen bands are directed vertically, instead of horizontally like those of the deeper, native stroma. The elliptical graft formation fills the upper dermis in the location of the lost dermal elements, which are seen in the adjacent dermis. A mild, residual depression from the original scar process marks the location as a site of damage. (B) Fibroblasts infiltrate the graft matrix.

Several lesions in select individuals were punch biopsied and regrafted to monitor graft integration. In the area of untreated scars, there was an absence of subepidermal elements and the ulcer was tethered to deeper tissues by collagen bands (Fig. 1). By 6 weeks after insertion, the graft was evident at the level of the skin appendages, approximately 2 mm below the skin surface, and lymphocyte hoards invaded the graft interstices (Fig. 2). Twelve weeks after grafting, the graft assumed a rounded or elliptical shape, the lymphocyte response subsided, and the collagen framework of the graft was still evident (Fig. 3A). Again, the graft assumed the space previously occupied by sebaceous glands, hair follicles, etc., and the epidermal indentation was restored. A moderate fibrblast population invaded the collagen framework, replenishing the matrix with endogenous collagen (Fig. 3B).


Fig. 4. Chicken pox scar before (A) and 4 months after (B) recollagenation.

Fig. 5. Wide deep cheek scar before (A) and after (B) recollagenation.

Clinical improvement was graded by the author approximately 24 weeks after treatment on the following scale: excellent/resolved: 75% to 100% improvement in contour; good: 50% to 75%; fair/poor: 0% to 50%. By this appraisal, 14 cases were graded as excellent/resolved, 23 as good, and seven as fair/poor. Repeat treatment was offered to good and fair results for consideration. Case examples are presented in Figures 4 through 6.


Fig. 6. Forehead scar before (A) and after (B) recollagenation.

Discussion

The insertion of allograft fascia lata into an intradermal plane is one form of recollagenation that is a convenient, effective means to restore the surface topography.[3,4] The needle dissection was simple and graft insertion took moments. Insertion of solid, freeze-dried material into individual scars was easier than insertion of fresh material and the banked material may have a higher fiber density because the tissue was dehydrated. In the author's experience, soft, rehydrated, cadaver dermis (Alloderm) was more difficult to handle than stiff, dried preparations and the healing process was similar. A 5-mm-square chip of banked fascia lata has a dry weight of approximately 40 mg of fibrous matrix compared with 35 mg in 1 mL of Zyplast collagen.

Scar management by surgical revision may reach an endpoint at which some finer defects are unresponsive to further excision or loose tissue for advancement is not available. Scar refinement techniques, such as dermabrasion or laserabrasion often will not induce sufficient collagen to replenish the tissue loss and achieve a level epidermis.[7,8] Soft tissue replacement of lost collagen should ideally occur with native collagen, reserving fat injections for specific areas of fat loss.

Besides intradermal applications of banked human fascia lata, numerous reports have documented its efficacy as a tissue substitute since it was first introduced into the medical literature by Koontz in 1926.[9-11] Multiple histologic reports from animals indicate that the graft matrix is progressively subtituted with vascularized, native collagen, which should survive indefinitely.[9-11] The histology presented in this investigation of human facial skin showed a similar tme course and pattern of tissue healing as in those animal studies, verifying the volume enhancing effect of preserved fascia lata, as well as the propagation of teh native collagen response.[12-14] Therefore, recollagenation is suggested as an appropriate adjunct for scar restoration.